It has been recognized for many years that in cold temperatures heating diesel fuel is sometimes necessary to keep the fuel flowing. This is because diesel fuel tends to become thicker at cooler temperatures which reduces its ability to flow through fuel lines and filters. Many types of fuel heating devices have been devised over the years to heat diesel fuel. Some of these devices are mounted on diesel powered vehicles and are controlled by the operator. The operator's involvement in controlling the device may result in failure to heat the fuel when required or unnecessary heating of the fuel.
In recent years, electronic fuel control systems have been used on engines, including fuel injected diesel engines. For efficient operation, these electronic fuel systems require that the fuel temperature be within specified limits. If the fuel temperater exceeds these limits, the system will not function properly. Also, high fuel temperatures may result in loss of engine power.
Applicant is unaware of any prior devices that both cool and heat the fuel as required to maintain the fuel being supplied to the engine within a desired range. Thus there exists a need for such a device.